The Arab Spring originated on December 17, 2010 in Tunisia, where widespread protests led to the overthrowing of long-time dictator and President Ben-Ali. From there the revolution spread to Egypt, Yemen, and Algeria before moving across the entirety of North Africa and the Middle East. 

The Russian Revolution of 1917 was caused by widespread anger among among the Russian populace towards the Czarist government due to frustration with the conduct of World War I and mass famine. The Czar abdicated and a Provisional Government under Alexander Kerensky took control of the state. However, the Provisional Government refused to end the war with Germany, which dramatically weakened its popularity and helped to allow the Bolsheviks under Lenin to take control in 1918.

Kennedy's assassination brought in the presidency of his vice president at the time, Lyndon B. Johnson. Johnson thus held the office prior to being elected; Johnson was elected for the first time in 1964, although he served as president from 1963-8.

In the years leading up to the Boxer Rebellion, both European and Japanese powers competed to establish spheres of influence in China, effectively taking control of much of the country's economy. The Boxers, or the Society of Righteous and Harmonious Fists, primarily wanted these foreign powers out. They did kill missionaries and take over embassies as well, but both of those tactics were seen as means to an end. The Boxer Rebellion should not be confused with Mao Zedong's communist takeover of China after World War II.

Mussolini came to power in Italy in 1922 as head of the Fascist Party and elected leader of the Italian government. Italy, at the time, was suffering from extreme economic hardship. Mussolini promised rapid economic growth and Italian territorial expansion. In 1925 Mussolini declared himself dictator for life.

Emiliano Zapata and Pancho Villa were both instrumental in the Mexican Revolution and the subsequent establishment of the Mexican Republic. Villa led the revolutionaries in northern Mexico, whereas Zapata led peasant rebellions in southern Mexico. Together they are more responsible than any other revolutionaries for the successes of the Mexican Revolution.

Throughout much of the 1960s public opinion of the Vietnam War was fairly evenly split, but it began to turn against the war in the late 1960s and this was compounded by the election of President Nixon. Within a year of Nixon’s election less than a third of the population was in support of the Vietnam War.

Mustafa Kemal led the Turkish independent movement following the destruction of the Ottoman Empire at the end of World War Two. He is credited with founding the Turkish Republic and he served as the first President of Turkey. His time in power is marked by a series of modernizing reforms, including universal public education and the elevation of the status of women.

Hitler came to power in Germany in 1933. He was appointed Chancellor of Germany by the President of the Weimar Republic. Once in power as Chancellor, Hitler and the Nazis worked to consolidate power and quickly quashed opposition. In 1934 they held a referendum in which Hitler was elected as dictator of the nation. The election was highly controversial and contentions as the Nazi Party worked to manipulate public opinion and suppress opposition.

The reform policies of glasnost and perestroika were initiated by Mikhail Gorbachev in the Soviet Union in the 1980s. The primary purpose of glasnost, which means "openness" was to improve the transparency of the Soviet political system and allow more people to be included in the political process.